fix(xlsx/xls): skip completely empty sheets that emit broken tables

packages/markitdown/src/markitdown/converters/_xlsx_converter.py

@@ -134,6 +134,12 @@ def convert(
         sheets = _read_xlsx_sheets(file_stream)
         md_content = ""
         for s in sheets:
+            # A completely empty sheet has no columns. pandas then emits a
+            # column-less HTML table that markdownify turns into broken syntax
+            # ("|\n|  |"). Skip it. A header-only sheet still has columns and
+            # already renders as a well-formed empty table.
+            if sheets[s].columns.empty:
+                continue
             md_content += f"## {s}\n"
             html_content = sheets[s].to_html(index=False)
             md_content += (
@@ -196,6 +202,10 @@ def convert(
         sheets = pd.read_excel(file_stream, sheet_name=None, engine="xlrd")
         md_content = ""
         for s in sheets:
+            # Same empty-sheet guard as XlsxConverter: no columns means pandas
+            # would emit a column-less table that is not valid Markdown.
+            if sheets[s].columns.empty:
+                continue
             md_content += f"## {s}\n"
             html_content = sheets[s].to_html(index=False)
             md_content += (

packages/markitdown/tests/test_xlsx_empty_sheet.py

@@ -0,0 +1,60 @@
+import io
+
+from openpyxl import Workbook
+
+from markitdown import MarkItDown, StreamInfo
+
+
+def _xlsx_bytes(workbook: Workbook) -> bytes:
+    buf = io.BytesIO()
+    workbook.save(buf)
+    return buf.getvalue()
+
+
+def test_completely_empty_sheet_is_skipped() -> None:
+    """A sheet with no columns must not emit malformed table syntax."""
+    workbook = Workbook()
+    workbook.active.title = "HasData"
+    workbook.active["A1"] = "col"
+    workbook.active["A2"] = "v"
+    workbook.create_sheet("CompletelyEmpty")
+
+    result = MarkItDown().convert_stream(
+        io.BytesIO(_xlsx_bytes(workbook)),
+        stream_info=StreamInfo(extension=".xlsx"),
+    )
+
+    assert "## HasData" in result.markdown
+    assert "| col |" in result.markdown
+    assert "| v |" in result.markdown
+    assert "CompletelyEmpty" not in result.markdown
+    assert "|\n|  |" not in result.markdown
+
+
+def test_header_only_sheet_keeps_empty_table() -> None:
+    """A sheet with a header row but no data already produces a valid table."""
+    workbook = Workbook()
+    workbook.active.title = "HeaderOnly"
+    workbook.active["A1"] = "col"
+
+    result = MarkItDown().convert_stream(
+        io.BytesIO(_xlsx_bytes(workbook)),
+        stream_info=StreamInfo(extension=".xlsx"),
+    )
+
+    assert "## HeaderOnly" in result.markdown
+    assert "| col |" in result.markdown
+    assert "| --- |" in result.markdown
+
+
+def test_single_completely_empty_workbook_emits_nothing() -> None:
+    workbook = Workbook()
+    workbook.active.title = "Empty"
+
+    result = MarkItDown().convert_stream(
+        io.BytesIO(_xlsx_bytes(workbook)),
+        stream_info=StreamInfo(extension=".xlsx"),
+    )
+
+    assert result.markdown.strip() == ""
+    assert "|" not in result.markdown